Pigment epithelium-derived factor inhibits angiogenesis and growth of gastric carcinoma by down-regulation of VEGF

Previous studies have shown that pigment epithelium-derived factor (PEDF) is an antitumor candidate with anti-oxidative, anti-inflammatory and anti-angiogenesis properties. However, the effect of PEDF on gastric carcinoma has not been elucidated. MTT assay and Annexin V/PI staining were performed. Immunohistochemistry was applied to detect microvessel density (MVD) of a xenograft model. The protein levels of vascular endothelial growth factor (VEGF) were examined by Western blot analysis and hypoxia-inducible factor-1 alpha (HIF-1 alpha) translocation was investigated by immunofluorescence. Results showed that growth and angiogenesis of gastric carcinoma were suppressed after PEDF injection. PEDF could not directly suppress proliferation or induce apoptosis of gastric carcinoma cells. However, the expression of VEGF both in tumor tissues and gastric carcinoma cells was down-regulated by PEDF. The amount and nuclear translocation of HIF-1 alpha, the transcription factor of VEGF, was also inhibited by PEDF. In conclusion, PEDF suppresses angiogenesis and growth of gastric carcinoma by down-regulating HIF-1 alpha and VEGF and may have potential for gastric carcinoma treatment.